Poster Presentation ESA-SRB 2023 in conjunction with ENSA

Impact of the current lack of standardisation on the validity of pathological assessment of pituitary tumours: What clinicians need to know. (#250)

Prishila Fookeerah 1 2 , Winny Varikatt 3 4 , Mark Mclean 1 2
  1. Department of Diabetes and Endocrinology, Westmead Hospital, Sydney, NSW, Australia
  2. School of Medicine, Western Sydney University, Sydney, NSW, Australia
  3. Department of Tissue Pathology and Diagnostic Oncology, Westmead Hospital, Sydney, NSW, Australia
  4. Westmead Clinical School, University of Sydney, Sydney, NSW, Australia

Background

The application of transcription factor(TF) analysis has transformed understanding of the biology of pituitary tumours. However, there remains a high degree of heterogeneity in epidemiological and clinical patterns seen in different studies, precluding the development of clinical guidelines for histological subtypes. We conducted a systematic review and meta-analysis of methodological and diagnostic criteria in recent studies, exploring inconsistencies in the literature.

Methods

A PubMed search was conducted with keywords “pituitary tumour”, “classification”, “transcription factor” and “clinicopathological”. Abstracts of studies involving pituitary tumours, published in English between 2015 to February 2023 were screened for relevance. Studies including all 3 TF were evaluated for methodology, antibody type and scoring strategy. Proportion of tumour subtypes was assessed.

Results

Nine of thirteen identified studies were retrospective and used stored tissue blocks. Mean storage time of oldest specimens used in retrospective studies was 17.1 +/- 6.8 years at time of publication. There was a positive linear correlation between percentage of null cell (NC) tumours and the age of tissue analysed (R2= 0.71, p=0.03). Threshold definitions for positive identification of tumour types varied from 5% to 80% positive tumour cells. Higher cut-off did not allow detection of plurihormonal tumours. Five studies reporting clinical data indicated that 33-100% of NC tumours showed radiological invasion. In the non-functioning tumour category, estimated proportion of lineage-based subtypes was: 5.6% (95% CI 4.6-6.7%) silent PIT1, 18% (16.7-20.1%) silent corticotroph tumours, 68% (66-70%) gonadotroph tumours. Significant heterogeneity was observed, with I2 of 81.7%, 71.7% and 75.7% in each group (p<0.0001).

 

Conclusion

There is marked heterogeneity in proportion of tumour subtypes in studies. Higher incidence of NC tumours is seen with older tumour specimens, possibly representing false negative staining. Plurihormonal tumours can be missed if higher positivity cut-off is applied. Non-standardization of methods poses problems for clinical interpretation of results.